1. Field of the Invention
The invention relates to the field of inspection devices and in particular to an improved device for inspecting the contour and angular tolerances of parts such as long extrusions.
2. Background of Prior Art
The prior art method for inspecting parts such as long extrusions, castings, or forgings to determine whether they were in tolerance was time consuming to perform and thus expensive. Typically, a plurality of gauge blocks are placed on an inspection table and brought into contact with an accurately dimensioned template at various inspection locations thereon. The gauge blocks are then secured to the inspection table. The part to be inspected is then brought into contact with as many of the gauge blocks as possible. The gap between any one gauge block and the part indicates a discrepancy with the ideal dimension. In order to determine whether the part is within tolerance, feeler gauges are inserted into the gap. This is obviously a time consuming operation and there is also a considerable chance for error.
An example of this approach is U.S. Pat. No. 2,807,092, Check Assembly by E. E. Jones. Jones' procedure is to mount a template on an inspection table and locate a plurality of gauge members in abutting relationship along the template. The part to be inspected is then aligned on the template and the gap between the gauges blocks and part is measured by go-no go feeler gauges. While making the template an integral part of the inspection procedure reduced the time required to set up the gauge blocks, inspection of the part was not automatic. Further, a large number of gauges must be stocked in order to accommodate parts with different angles.
Another similar approach can be found in U.S. Pat. No. 3,203,100, Checking Fixtures and Method of Making by L. J. Hegedus. Hegedus forms the individual gauge blocks from plate stock by punch forming tabs in the plate and rotating the tabs upright. While this method provides a low cost set of gauge blocks for inspecting the contour and angle of an extrusion or the like, the position of the gauge blocks are set and cannot be changed, and, thus, only one type of part can be inspected. Furthermore, the part must still be checked by the use of feeler gauges.
Therefore, it is a primary object of this invention to provide a device for rapidly and accurately inspecting discrete portions of a part to determine whether they are within allowable tolerances.
It is another object of this invention to provide a device that can inspect a plurality of different parts having different contours and contour tolerances at discrete locations.
It is a further object of this invention to provide a device that can inspect a plurality of different parts having both different contours and angles, with different tolerances at discrete locations.